The present invention relates generally to yarns, fabrics and protective garments knitted of such yarns. More particularly, the present invention relates to a cut-resistant composite yarn construction which provides effective cut resistance for a protective garment without the use of expensive high performance fibers.
In many industries, it is desirable to provide protective garments, particularly gloves, to protect employees from being cut. Ideally, such garments should provide an acceptable amount of cut resistance while possessing suitable flexibility and durability. To this point knit garments having these qualities have been constructed from yarns that include xe2x80x9chigh performancexe2x80x9d fibers to achieve enhanced cut resistant performance. These yarns are constructed using wrapping technique wherein in a core comprising of a single or multiple strands is wrapped with one or more additional strands. Either the core or the wrap strands may include strands comprised of a high performance fiber. Typical of these include the cut resistant yarn disclosed in U.S. Pat. Nos. 4,777,789; 4,838,017 and 5,119,512. These patents disclose the use of well-known xe2x80x9chigh performancexe2x80x9d fibers which, as used herein, means fibers such as extended chain polyethylene (Spectra(copyright) brand fiber by Allied) or aramid (Kevlar(copyright) brand fiber by DuPont).
The use of these high performance fibers to make cut-resistant composite yarns and garments has not come without certain disadvantages. First, articles made from these high performance fibers may be stiff and, particularly in the case of protective gloves, may cause the wearer to lose a certain amount of tactile sense and feedback. This lose of sensitivity can be important for workers in the meat processing industry.
Another potential drawback to the use of high performance fibers is their cost. For example, the unit length cost for high performance fiber easily may be several times that of the next most expensive component of a composite, cut-resistant yarn. It would be very desirable to substantially reduce or eliminate the high performance fiber content of a cut-resistant composite yarn.
There remains a need for a cut-resistant yarn construction offering an effective level of cut resistance performance at a cost savings compared to composite yarns that include high performance fibers.
The present invention relates to a cut-resistant composite yarn that includes a core of a fiberglass strand(s) wrapped with one or two fine metal strands, which combination provides the cut-resistant properties of the yarn. The fiberglass core and wire wrap is covered by one or two core strands of a conventional material. It has been discovered that the combination of a wire strand or strands wrapped around a soft fiberglass core provides a cut resistance performance that rivals that of cut-resistant yarns having the more expensive high performance fibers. Even if the cut resistance performance of the yarn of the present invention does not match exactly that of a cut-resistant yarn including a high performance fiber, the performance levels are acceptable. Significantly, these acceptable performance levels are achieved at great cost savings because of the elimination of the high performance yarn. Further, the fiberglass core with a single wrap of wire exhibits enhanced flexibility.
More specifically, the yarn of the present invention includes one or two fiberglass core strands having a total denier of between about 100 and about 1200 and at least one wire strand wrapped about the fiberglass core strand. A second wire strand may be wrapped around the first wire strand in a direction of wrapping opposite that of the first wire strand. The wire strands(s) should be no greater than 0.0030 inches in diameter and preferably between 0.0013 and 0.0030 inches. The yarn further includes a non-metallic, non-high performance fiber cover strand of a more conventional material wrapped around the core in a direction of wrap opposite that of the wire strand immediately there beneath. A second non-high performance fiber cover strand may be wrapped around the first cover strand in a direction opposite that of the first cover strand direction. If desired, the composite cut-resistant yarn of the present invention may further include a second fiberglass or wire strand in the core positioned adjacent to the first fiberglass strand.
These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiments when considered in conjunction with the drawings. It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention.